1. Technical Field
This invention generally relates to computer systems, and more specifically relates to ways to optimize computer programs.
2. Background Art
Since the dawn of the computer age, computer systems have evolved into extremely sophisticated devices, and computer systems may be found in many different settings. Dramatic advances in both hardware and software (e.g., computer programs) have drastically improved the performance of computer systems. Modem software has become very complex when compared to early computer programs. Many modem computer programs have tens or hundreds of thousands of instructions. The execution time (and hence, performance) of a computer program is very closely related to the number of instructions that are executed as the computer program runs. Thus, as the size and complexity of computer programs increase, the execution time of the computer program increases as well.
Unlike early computer programs, modem computer programs are typically written in a high-level language that is easy to understand by a human programmer. Special software tools known as compilers take the human-readable form of a computer program, known as “source code”, and convert it into “machine code” or “object code” instructions that may be executed by a computer system. Because a compiler generates the stream of machine code instructions that are eventually executed on a computer system, the manner in which the compiler converts the source code to object code affects the execution time of the computer program.
Many known compilers include optimizers that perform optimizations that decrease the execution time of a computer program. One type of known optimizer is a profiling optimizer that monitors the code as it runs, collects performance data known as profile data, then uses the profile data to make optimizations to the code. While these types of optimizers effectively improve the performance of the code, they do not address many aspects of the code that could benefit from further improvements. For example, when a computer program accesses a database, known optimizers do not take into account any information relating to the database in making their optimizations. Without improved apparatus and methods for optimizing a computer program that take into account characteristics of a database referenced in the computer program, the computer industry will continue to suffer from computer code that has not been fully optimized.